5.2.3 Common Mode Voltage < +/-10V / Single-Ended Inputs
This is not a recommended configuration. In fact, the phrase common mode has no meaning in a
single-ended system and this case would be better described as a system with offset grounds. You can try
this configuration, no system damage should occur and you may receive acceptable results.
5.2.4 Common Mode Voltage < +/-10V / Differential Inputs
Systems with varying ground potentials should always be monitored in the differential mode. Care is
required to assure that the sum of the input signal and the ground differential (referred to as the common
mode voltage) does not exceed the common mode range of the A/D board (+/-10V on the
PCIM-DAS1602/16). Figure 5-6 below show recommended connections in this configuration.
Figure 5-6. Common Mode Voltage < +/-10V / Differential Inputs
5.2.5 Common Mode Voltage > +/-10V
The PCIM-DAS1602/16 will not directly monitor signals with common mode voltages greater than
+/-10V. You will either need to alter the system ground configuration to reduce the overall common
mode voltage, or add isolated signal conditioning between the source and your board. See Figure 5-7 and
5-8 below.
Figure 5-7. Common Mode Voltage > +/-10V. Single-Ended Input
16
+
-
In p u t
A m p
To A /D
A /D B o a rd
I/O
C o n n e c to r
LL G N D
C H H igh
C H L ow
S ig n a
l S ou
rce
w it
h C o m
m on
M o d
e Vo l
tage
S ign a l so urce a n d A /D b o a rd
w ith c o m m on m o d e vo lta g e
con n ecte d to a d iffe ren tia l in p u t.
G N D
T he vo lta g e differen tia l
b etw een the se g ro un d s,
a dde d to the m ax im u m
in pu t sig na l m ust sta y
w ith in + /-10 V
S ys te m w ith a La rg e C o m m o n M o d e Volta g e ,
C o nn e cte d to a S ing le -E n d e d Inp u t
I/O
C o nn ector
+
-
Inp ut
A m p
To A /D
L L G N D
C H IN
A /D B o a rd
L
a rg e
c o m m
o n
m
o d e v
o lta g e
be t
w e e n
s ig na
l
so u rc
e & A
/D b o
a rd
G N D
Iso latio n
B arrie r
W h e n th e vo ltag e diffe re nc e
b e tw ee n s ig n a l s o urc e a n d
A /D b o a rd g ro u nd is la rg e
e n o u g h so the A /D b o a rd ’s
c om m o n m o d e ra n ge is
e xc e ed e d , is o la te d s ig na l
c on d itio n in g m us t be a d d e d .
Содержание PCIM-DAS1602/16
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